The removal of sulfur-based species from liquid or gaseous hydrocarbon streams is a long-standing problem in many industries. Hydrogen sulfide is a significant problem in the oil industry, particularly in the drilling, production, transportation, storage, and processing of crude oil, as well as waste water associated with crude oil, naphtha, fuel, and distillate oils. The same problems exist in the natural gas industry.
The presence of sulfur-containing compounds such as hydrogen sulfide can result in the deposition of sulfur containing salts which cause plugging and corrosion of transmission pipes, valves, regulators and other process equipment. Hydrogen sulfide is also toxic and, therefore, desirable to be removed. Even flared natural gas needs to be treated to avoid acid rain generation due to SOx formation. Also, in the manufactured gas or coke making industries, coal-gas emissions containing unacceptable levels of hydrogen sulfide are commonly produced from destructive distillation of bituminous coal.
Since hydrogen sulfide has an offensive odor, and fluids such as petroleum products and natural gas contain it, such fluids are often called “sour.” Treatments to lower hydrogen sulfide are often referred to as “sweetening” processes. When a particular compound is used to remove or lower H2S and mercaptans, it is called scavenging agent.
Conventional nitrogen-containing scavengers such as triazines cause scaling issues and may cause fouling in refineries. Existing non-nitrogen containing scavengers like acrolein and glyoxal can be used for scavenging hydrogen sulfide, however each has their own undesirable properties. For example, acrolein is toxic, and glyoxal is slow acting.
Despite the availability of scavengers for use in the oil and gas industry, there still exists a need for improved compounds, compositions and methods for removing sulfur-based species from liquid and gas streams. Such improvements include nitrogen-free scavengers and scavengers with increased dispersion into the sour hydrocarbon.